As the home of Violet Crawley, Dowager Countess of Grantham, played by Dame Maggie Smith in ITV's Downton Abbey, the chronicles of the historic Byfleet Manor continue to be added to.

But it was a far more down to earth procedure that led to the private home revealing its latest secret: a previously undocumented room beneath the floorboards.

Once a residence of Queen Anne of Denmark, wife of James I, and a favourite haunt of the poet Geoffrey Chaucer, Dave Harris, managing director of Orchard ICT, spent several days exploring the nooks and crannies of the house when looking to update it with the latest technology.

A sensitive process, it still came as some surprise when lifting floorboards to discover a seven-foot square hidden room between the floors.

With no doors but fully wallpapered and a bricked up window, whether the room was a priest hole or a hideout for soldiers or someone’s lover is unknown.

It’s not Byfleet Manor’s only unexplained secret, however. In the basement, there are four wooden steps ascending to meet the wall; what lies beyond is a mystery and because of the way the house is built, no one can work out where the other side of the wall is in relation to the staircase.

There is also believed to be a tunnel to the ruins of Newark Abbey at Pyrford, but no one has yet been brave enough to explore it.

Situated in 24 acres of Surrey countryside, Byfleet Manor is a now private home owned by Julie Hutton who describes herself as having the honour of being its current caretaker.

By prior arrangement, Downton Teas are served in bone china cups on a silver platter and you can book private tours of the manor house and gardens. Visit byfleetmanor.com for more information.